When Tarantino takes B-movie fodder and supercharges it with style, the results sizzle with illicit fun. But when filmmaking twins Logan and Noah Miller attempt the same thing, rehashing vulgar revenge-fantasy tropes in their hollow neo-Western “Sweetwater,” the schlock hits the fan. Peeved that a local religious zealot murdered her Mexican husband, an ex-prostitute grabs her guns and serves up retribution in a purple dress — a reversal on the sincere and decidedly less sensational promise of the Millers’ semi-autobiographical debut, “Touching Home.” Once again, though, by allying themselves with name actors, the brothers have ensured at least a modest release.

Boasting a script ripe with overwrought, pseudo-“Deadwood” dialogue, “Sweetwater” provides three roles enticing enough to have attracted thesps deserving of better material. Spewing nonsensical fire and brimstone over the opening stretch, Jason Isaacs plays the self-appointed prophet Josiah, a man who freely takes what he wants and invents vaguely biblical-sounding sermons to justify his hypocrisy. Lately, what he wants is Sarah (January Jones), a red-headed beauty out of place in the unforgiving New Mexico territory, trying to forget her rough bordello upbringing and reinvent herself as a pioneer wife. Rounding out the tense, three-way dynamic is Sheriff Jackson (Ed Harris), a lawman with a bowler hat and long, Old Testament hair dispatched to investigate two well-connected men who disappeared somewhere on Josiah’s land.

It’s no mystery what happened to the missing men (played by the Millers, well-disguised behind scraggly beards and rotted teeth): The film plainly shows them both being shot for sport by Josiah in the opening minutes, and it’s soon clear that the pernicious cult leader trumps what little law exists in the town. But the pic never explains why he holds such power, and it flies against the wisdom of Westerns that a man of God, however power-hungry, would find himself at the top of the frontier food chain.

Even so, Josiah has amassed a small cult of followers who attend church services (and offer their women for decidedly un-Christian bedroom duty) in what looks like a big barn surrounded by giant white crucifixes. This is clearly not the West as it ever existed in history, but rather a blank canvas on which the pic intends to create a new cadre of archetypes. Instead, it despoils the authentic New Mexico landscapes with unbelievable characters and patently contrived situations.

Incidents are clearly headed toward a three-way showdown, where none of the parties qualifies as pure. Sarah may have the least to answer for her past, having suffered the murder of her husband (Eduardo Noriega), the harassment of the townsfolk and a gratuitous miscarriage, which the Millers tastelessly exploit for a few less-than-mythic beauty-shots of her grieving against the sunset. Still, the scenes serve to return the ex-prostitute back to a place from which she has nothing to lose.

By rendering everyone in “Sweetwater” guilty of some crime or other, the film is free to set Sarah loose upon her tormentors. Thirty years ago, drive-in auds would have greedily devoured the ensuing carnage, cheering as Sarah baits Josiah’s henchmen by bathing topless before shooting them dead. The Millers endeavor to portray these sophomoric altercations as artfully as possible, but fancy-sounding dialogue and handsome widescreen lensing goes only so far to disguise the shallowness of the underlying material.

While some may call this a strong female role, and a certain straining for respect suits Sarah’s situation, Jones still feels trapped by the pre-feminist notions that confine her on “Mad Men.” Harris, who doubles as producer, puts a jester-like spin on the sheriff. The thesp previously starred in the Millers’ debut, about which they wrote a book describing their uncanny ability to convince professionals to support their vision. After “Sweetwater,” they have more explaining to do.